1. Field of the Invention
The present invention relates generally to an editing system utilizing an information recording and/or reproducing apparatus, such as a video tape recording and reproducing apparatus. More specifically, the invention relates to an editing control system in the editing system, which can shorten the period of time required to pre-view action during editing.
2. Description of the Background Art
As is well known, the editing involves repeated viewing of a section of the tape loaded in a playback side of a video tape recorder, which will be hereafter referred to as "P-VTR", to confirm and set the editing point to record video information on a master tape. In order to perform this operation, hereinafter referred to as the pre-view operation, the editing system performs a master pre-view operation for reading the video image recorded on the master tape and displaying the video image on a monitor, and a player pre-view operation for reproducing only the video image reproduced by the p-VTR to be recorded on the master tape and producing a black display image during the preceding and following periods.
As a practical matter, in the player pre-view operation, the editing system switches the image on the monitor from the black image to the reproduced image at a cut-in point at which a servo-lock is active. This makes it possible to easily confirm the editing point.
However, the time required for establishing the servo-lock, which will be hereafter referred to as the "servo-lock period", is variable in each video tape recorder (VTR). Therefore, when a VTR which has a long servo-lock period is employed as the p-VTR, if the tape is not rewound to a point which sufficiently precedes the edit point it has the result that the servo lock does not function properly. For this reason, the pre-roll time which represents a number of frames on the video tape loaded on the p-VTR, is set to be longer than the servo-lock period. This assures establishment of the function servo-lock condition before the display image is switched from the black image to the reproduced image.
On the other hand, prolongation of the pre-roll time clearly causes prolongation of the period required to reach the cut-in point. This considerably decreases the efficiency of the editing operation.
In the usual editing operation, the video image output from the p-VTR is recorded on the master tape. Therefore, most editing time is spent in player pre-view operation. In order to set each editing point, the pre-view operation is repeated several times. If the player pre-view time is prolonged, this naturally causes the editing time to be prolonged.